1. Technical Field of the Invention
The present invention relates to a device for saw chain lubrication, especially in connection with a hand-held device, e.g. a chain saw, said device including a pump that in its turn includes a pumping house, a piston that is received in the pumping house and means to bring the piston to rotate and simultaneously perform a reciprocating motion in the longitudinal direction of the piston, said means including on one hand a worm pinion having means for driving cooperation with a prime mover and on the other hand and a gear pinion mounted on the piston. The invention also relates to a worm pinion, preferably included in a device for saw chain lubrication.
2. Prior Art
As regards the pumping device that is to supply lubricant to the chain of a chain saw, said device can either be driven directly by the crank shaft or driven by the clutch drum mounted on the crankshaft.
In case the pending pumping device is driven by the crankshaft, said pumping device will be activated, i.e. pumping lubricant, as soon as the engine of the chain saw is running, i.e. the pumping device will be activated also during idling mode of the chain saw. In connection with this principal solution it is previously known to provide a worm pinion on the crankshaft by attaching a spirally wound spring wire on the crankshaft, said spring wire being fixed on the crankshaft by for instance a clamping joint.
Out of consideration for the environment the pumping device for supplying lubricant has been mounted on the clutch drum. This means that the pumping device is activated only when the chain is driven, i.e. the pumping device is not activated during idling mode of the chain saw.
It is previously known to mount a worm pinion of plastic on the clutch drum, said worm pinion cooperating with a gear pinion of metal that is mounted on the piston of the pumping device.
It is also previously known to mount a worm pinion of metal on the clutch drum, said worm pinion cooperating with a gear pinion of plastic that is mounted on the piston of the pumping device.
For strength reasons it has turned out to be necessary that at least one of the cooperating pinions is manufactured from a wear resistant material, preferably metal.
A primary object of the present invention is to provide a device of the type mentioned above, said device having cooperating components that are cheap to manufacture and still provide a reliable availability performance.
A further object of the invention is that the materials of the components included in the device are selected depending on the function that said component is to perform.
A further object of the invention is that the structure and function of the device pays attention to the environment.
At least the primary object of the present invention is realized by means of a pumping device (1) in connection with saw chain lubrication, in connection with a hand-held chain saw, said pumping device (1) including a pumping house (7), a piston (9) that is received in the pumping house (7) and means (3, 10, 11, 12) to bring the piston (9) to rotate and simultaneously perform a reciprocating motion in its longitudinal direction, said means including on one hand a worm pinion (3) having means (25) for driving cooperation with a prime mover (15, 19) and on the other hand a gear pinion (10) mounted on the piston (9), characterized in that said worm gear (3) on one hand includes a spirally shaped element (28) that is prefabricated as a separate detail and intended to cooperate with the gear pinion (10), and on the other hand a sleeve shaped element (18) that supports the spirally shaped element (28), and that the spirally shaped element (28) is manufactured from a metal, and that the sleeve shaped element (18) and the teeth of the pinion (10) are manufactured form a polymer material.